Mark 708BS Series
Bellow Stem Seals Fractional Flow Control Valves
Bellows stem seals eliminate fugitive emissions by surrounding the valve stem with a pressure-tight barrier, isolating the stem from the process fluid and preventing leakage to the atmosphere. For an extra measure of protection, the bellows stem seal option provides a back-up seal of Teflon or Graphite/Grafoil packing along with a threaded or NPT detection port for use in monitoring potential emissions leakage.
- Pilot plant installations
- Test stands
- R & D facilities
- Processing plants
- Fugitive emissions
- Hazardous service
Industries
- Aviation & aerospace
- Chemical, refining & petrochemical
- Oil & gas
- Process or industrial
- Test Equipment & Services
- Rolling diaphragm
- Standard bonnet port for use in lubricating the packing for added protection against leakage or for use as a detection port for monitoring potential fugitive emissions
- Tri-ply bellows provides added strength and enhanced performance
- Interchangeable trim sets
- Threaded bonnet for easy removal of the bellows assembly
- Bolted body/bonnet connection
- Optional side mounted or top mounted positioner
Size Type: Globe – Class IV or VI
Sizes: 1/4″ – 3/4″ (DN8 – DN20)
End Connections: Threaded, Socket Weld, Integral Tube, Welded Flange
Body Materials: Carbon Steel, Stainless Steel, Hastelloy C, Monel, Alloy 20, others
Cv (Kv): 0.00001 to 4.0 (0,000009 to 3,4)
Ranges: 3-15 or 6-30 psi; split ranges are available with optional positioner
Installation and Maintenance Videos
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CRN Number
ATEX Certified
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Mark 708 Series
Precision Control, Fractional Flow Control Valve
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